The stratospheric polar vortex is visualized with polar maps of the Potential Vorticity (PV) on an isentropic surface.
This surface is defined by a potential temperature of 485K, i.e. in the lower stratosphere where polar ozone depletion happens.
The mosaic of maps below are derived from a subset of the
Medium Range Ensemble Forecast started daily (at 00UT) by ECMWF. The forecasts are produced for the 14th day
(since 2016/03/23, 9th and 15th day before).
The primary intention is to allow a subjective evaluation of the probability of vortex splits during the polar Spring.